Ordinarily they should prorate the first month. Basically break down a month and divide by days in the month. So if you moved in say February 14th that gives you two weeks of rent to be paid instead of an entire month. So if your monthly is 600, it would be 150 a week or 21.43 per day. I would think you should pay $850 until the end of March. Then not pay again until April 1st